纳米材料结合的dsRNA对烟草花叶病毒侵染的抑制

基于病毒基因的外源双链RNA（dsRNA）可以在植物体内诱导RNAi，但dsRNA易降解、作用时间有限，限制了这项技术的应用。本研究以TMV衣壳蛋白（CP）基因为目的片段，体外合成dsRNA，分别与2种纳米材料壳聚糖（chitosan，CS）和层状双氢氧化物（layered double hydroxide，LDH）融合，合成CS-dsRNA和LDH-dsRNA 2种制剂。测试了2种制剂的稳定性及其对TMV的预防和治疗效果。结果表明，在4、25和37℃，30 d的稳定性测定试验中，dsRNA的量较初始值分别减少了80.01%、58.89%和59.76%，降解比较明显，dsRNA在4℃的降解速率略高于在25和37℃的降解速率；CS-dsRNA制剂中dsRNA的量较初始值分别增加了65.98%、103.82%和157%，LDH-dsRNA制剂中dsRNA的量较初始值分别增加了54.30%、58.4%和66.42%，dsRNA被CS与LDH 2种纳米材料包裹后降解率明显下降，而且随着温度的升高dsRNA的量有所增加，说明纳米材料融合的dsRNA有缓释效应。半叶法试验表明，dsRNA、CS-dsRNA和LDH-dsRNA对TMV的预防效果分别为60.12%、57.79%和55.18%，治疗效果分别为65.01%、58.40%和59.08%。本研究表明，纳米材料CS与LDH对dsRNA起到了良好的保护、缓释及提高稳定性的作用，在利用RNA干扰防治植物病毒病害中具有良好的应用前景。

Nanomaterials-dsRNA Prevent Tobacco Mosaic Virus Infection

Application of exogenous double-stranded RNAs targeted to viral genes can induce RNAi in plants, but dsRNA is easy to be degraded and only effective in a limited time, which limits the application of this technology. In this study, TMV coat protein gene was used as the target fragment to synthesize dsRNA in vitro, and then fused with two kinds of nanomaterials, chitosan (CS) and layered double hydroxide (LDH) to synthesize CS-dsRNA and LDH-dsRNA preparations. The stability of the two preparations was tested, and the prevention and therapeutic effects on TMV were also investigated. The results showed that the amount of dsRNA decreased by 80.01%, 58.89% and 59.76%, respectively, at 4℃, 25℃ and 37℃ for 30 days. The degradation rate of dsRNA at 4℃ was slightly higher than that at 25℃ and 37℃. The amount of dsRNA in CS-dsRNA preparation increased by 65.98%, 103.82% and 157%, respectively, and that in LDH-dsRNA preparation increased by 54.30%, 58.4% and 66.42%, respectively. With the increase of temperature, the amount of dsRNA increased, indicating that the nanocomposite dsRNA has a slow release effect. The experiment results of half-leaf method showed that the preventive effects of dsRNA, CS-dsRNA and LDH-dsRNA on TMV were 60.12%, 57.79% and 55.18%, and the therapeutic effects were 65%, 58.4% and 59.08%, respectively. This study showed that the nano-materials (CS and LDH) play a good role in the protection, slow release and stability of dsRNA, and a combination of nano-materials and RNAi have a promising application in the prevention and treatment of plant viral diseases.